#include<stdio.h>
//给字符串设置一个数，设置多少个
char *mymemset(char *arr1,char a,size_t num)
{
    char *ret=arr1;
    for(int i=0;i<num;i++)
    {
        arr1[i]=a;
    }
    return ret;
}
int main()
{
    char arr1[]="hello world";
    char a='a';
    int num=7;
    char *target=mymemset(arr1,a,num);
    printf("%s",target);
    return 0;
}
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